Machine Learning Scientist II

Expedia Group brands power global travel for everyone, everywhere. We design cutting-edge tech to make travel smoother and more memorable, and we create groundbreaking solutions for our partners. Our diverse, vibrant, and welcoming community is essential in driving our success.

Why Join Us?

To shape the future of travel, people must come first. Guided by our Values and Leadership Agreements, we foster an open culture where everyone belongs, differences are celebrated and know that when one of us wins, we all win.

We provide a full benefits package, including exciting travel perks, generous time-off, parental leave, a flexible work model (with some pretty cool offices), and career development resources, all to fuel our employees' passion for travel and ensure a rewarding career journey. We’re building a more open world. Join us.

You will be part of a team that builds the core algorithms that power Expedia Group’s advertising marketplace. We are looking for a hands-on scientist who is passionate about applying machine learning to complex prediction and optimisation problems that drive a global ecosystem of advertising partners and millions of travelers across Expedia Group’s B2C and B2B platforms.

The EG Advertising Machine Learning team builds the models and decisioning systems that power Expedia Group’s global advertising business, inspiring travelers with relevant, personalised recommendations and turning rich traveller and partner data into smarter targeting, bidding, and measurement. We own the full ML lifecycle - from problem framing and offline experimentation through model design, large-scale training, online A/B testing, and production deployment - working closely with product, engineering, and analytics teams to drive measurable revenue impact for both advertisers and EG.

In this role, you will:

• Implement & Validate ML Models: You will implement, test, and validate machine learning models, taking ideas from concept to production.
• Test, Learn, and Iterate: design and analyse rigorous A/B tests to validate your models, quantify their business impact, and proactively monitor and iterate on model performance.
• Collaborate and Learn: Partner effectively with senior scientists, engineers, and product managers to understand requirements and contribute to solutions. You will continuously deepen your understanding of our data, infrastructure, and problem space.

Minimum Qualifications:

• PhD or MS in a quantitative field (e.g., Computer Science, Economics, Statistics, Physics).
• 1+ years of hands-on industry experience building and deploying machine learning models to solve real-world problems.
• ML & Statistical Fundamentals: A strong foundation in machine learning theory (e.g., Supervised/Unsupervised Learning) and core statistical concepts. A strong grasp of the tools needed to measure impact, including experimental design (A/B testing).
• Technical Fluency: Proficiency in Python and its data science ecosystem (e.g., scikit-learn, pandas, PySpark). Experience with SQL for data querying is essential. Follow software engineering best practices and contribute to the team's shared codebase.
• Team player: You are a strong collaborator who can effectively partner with teammates to break down problems and implement solutions.
• First-Principles Problem Solver: Skilled at dissecting ambiguous problems and clearly communicating complex technical ideas.

Preferred Qualifications:

• Domain knowledge in online advertising or e-commerce.
• Experience building and deploying models using GenAI/LLM technologies